Bertil Guve was 10 years old when Ingmar Bergman recruited him to star in Fanny and Alexander. Bergman had spotted Guve in a bit part in a Lasse Hallstrom TV movie and had dispatched scouts to his school to look him over. "When they asked me to audition, I wasn't really interested," Guve recalls today. The Hallstrom movie hadn't been much fun. "People were in a bad mood and shouting at each other. There was a lot of anger going round." He had no idea who Bergman was. Guve's mother explained to him that Bergman was almost as famous in Sweden as John Wayne or Bjorn Borg. "And she added - don't worry! They won't choose you for the part."

To Guve's immense surprise, he was chosen to play Alexander (the character based on Bergman himself as a young boy). "I asked Ingmar later why he chose me. He said it was because I acted with my eyes." It helped, too, that Guve had a dreamy, slightly melancholy quality as well as a vivid imagination. (During his audition, he told a tall tale about having killed his grandfather, which greatly appealed to Bergman.)

Bergman didn't tell Guve what Fanny and Alexander was about. It was shot in chronological order. Only slowly did Guve realise this was a story about a young boy at war with his disciplinarian stepfather, the bishop. Despite the sometimes downbeat subject matter, the atmosphere on set was high-spirited and full of expectation - this was, after all, the largest film ever made in Sweden. Guve enjoyed himself, running amok during the breaks between shooting. "I'd get back and be all sweaty. My clothes would sometimes be dirty and the crew would panic."

Only once, when Guve started corpsing, did he witness the director's notorious temper. As he stood tittering in front of camera, Bergman exploded. "He jumped up and grabbed my arm and said, 'This is the most outrageous, the most unprofessional behaviour I have ever seen.'" The child star was left in tears. The next take went just as badly. Guve wasn't laughing - now he was crying. Bergman eventually took Guve into another room. "He put his arm around me. I cried. We talked. Everything was sorted out."

Fanny and Alexander won four Oscars and suddenly Guve started being recognised on the street. "On the one hand, my life went on just as normal. I went to the bus stand and waited for the bus to go to school," he recalls. "But I had to take into account that people knew who I was when I didn't know who they were."

Guve was half-Spanish, which led to some cultural misunderstandings. "After the film, I didn't really have the Swedish sense of being humble." But Guve soon realised that some Swedes thought he was showing off by talking about Fanny and Alexander. "I made the decision that I would never talk about the film unless someone asks me 15 or 20 questions and I know that they are really interested."

These days, Guve works for the Royal Institute of Technology in Stockholm. He and Bergman stayed in touch over the years. When Guve wrote a PhD thesis on Judgment and Conviction in Business Decisions he sent a copy to Bergman. "I don't know if he read it, but he sent me a message thanking me 'so much for the lovely book'."

And what about the farting? In one of the most celebrated scenes in Fanny and Alexander, Uncle Carl is shown breaking wind on the staircase for the entertainment of the kids. He is a virtuoso in the art, even able to blow out candles with his exhalations. No, Guve explains, the actor wasn't breaking wind for real. "They had a person sitting right next to the candle with a tube." If you study the scene carefully, you will notice that the wind that blows out the candle doesn't actually come from the direction of Uncle Carl's backside. "It comes from the side." So much for method acting.